George frederick wynne



(No Model.)

G. P. WYNNE.

ACTINOMETER.

No. 600.484. Patented Mar. 8,1898.

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dZ Z M UNITED STATES GEORGE FREDERICK \VYNNE, OF

PATENT OFFICE.

PLASGWYN, MINERA, ENGLAND.

ACTINOMETER.

SPECIFICATION forming part of Letters Patent No. 600,484, dated March 8, 1898.

Application filed February 12, 1897. Serial No. 623,091. (No model.)

T0 at whom it may concern.-

Be it known that I, GEORGE FREDERICK WVYNNE, a subject of the Queen of Great Britain, residing at PlasgwymMinera, near lVrexham, in the county of Denbigh, England, have invented. certain new and useful Improvements in Actinometers, of which the following is a full and complete specification, such as will enable those skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in actinometers and the object thereof is to provide an improved device for timing the exposure of platinotype, carbon, engineers sunprints, or any other printing process requiring development to bring out the latent image or for testing the speed of sensitive photographic plates or films.

The invention is fully disclosed in the following specification, of which the accompanying drawings form a part, in which- Figure 1 is a plan view of the device which I employ with the hinged lid or cover of the casing open; Fig. 2, a section on the line 2 2 thereof; Fig. 3, a plan view of a metal plate which forms a part thereof; and Fig. 4, a View similar to Fig. 2, showing a modification.

In the drawings forming part of this specification like parts of my improvement are designated by the similar numerals of reference, and in the practice of my invention I provide a metal casing 5, which is preferably rectangular in form and the bottom of which is open and provided with an inwardly-directed flange or rim 6, which extends entirely around the same, and the said box or casing is provided with a hinged cover 7.

Within the bottom of the box or casing is a plate 8, of opal glass, ground glass, or other translucent material, above which is placed a sheet 9 of thin metal or other opaque substance. The proportion of the opal glass and perforated metal plates may be reversed; but the best arrangement is to have the opal plate outside, as shown, as there is then no danger of the perforations becoming choked up with dirt. In this metal plate are formed a plurality of rows of perforations, which are des ignated by the reference-numerals 10, 11, 12, and 13, and said rows are preferably four in number, and said perforations in each row are graduated in size from one end to the other thereof, the first and third rows beginning at the left being preferably larger than the second and fourth, and above this metal plate are placed two similar plates 14 and 15, the first of which is composed of plain or ground glass and the other of opal glass or some simi lar translucent material of greater opacity than the other plate.

Above the plates 14; and 15 and separated therefrom by narrow packing-strips 16 is a transparent-plate 17 of glass or similar material, and on this plate I place the numerals from 1 to 16, inclusive, said numerals being arranged in two rows and in such manner that they are directly over the corresponding perforations in the rows of perforations .12 and 13 in the plate 9, and adjacent thereto are two rows of letters from. A to P,inclusive, which are arranged in a similar manner and directly over the corresponding perforations in the rows 10 and 11 in the plate 9. The narrow strips 16 are only put in to make up the thicknesses of the plates in the case, so that the plate with the figures on comes just flush with the top edge of the case. If the plates themselves exactly made up the thickness, the strips would not be required at all. They are not an essential part of the apparatus. These separate rows of numerals and letters are designated in Fig. 1 by the reference-numerals 18 and 19, respectively, and each numeral and letter is preferably inclosed by a small circle or circles 20, and these numerals and letters and circles are placed in the glass in the usual manner and show in black, and the entire upper surface of said glass is also preferably colored.

I also place in the hinged coveror lid 7 felt or other packing material 21, and said lid or cover is provided at each end with inwardlydirected spring projections 22, and ordinary strips 23, of sensitive silver printing-out paper, are placed in said lid or cover and held therein by said spring prongs or projections 22, and when the lid or cover is placed over the box or casing the sensitive strips 23 are pressed into contact with the hereinbeforementioned numerals and letters.

hen the lid or cover of the box is closed and the opal glass or translucent plate exposed to the light, the light passes through the said plate and the perforations in the metal plate 9 and falls upon the numerals and letters on the plate 17 and impresses said numerals and letters upon the sensitive-paper strips I have discovered that it is not necessary to separate by an opaque partition the light which falls upon one character from that which falls upon an other, but that if the thickness of the plain or ground glass and opal glass and the proportion in the size of the holes in the plate 9 and the characters are properly adjusted the light from one hole does not in any way interfere with the printing of any of said characters other than the oneimmediately opposite said holes, although there is only a transparent or translucent medium between the perforated plate and the characters. As the greatest amount of light passes through the largest holes or perforations upon the characters and a less quantity upon each of the succeeding characters in the same row, the result is that the characters over the largest holes or perforations, or those at the left, appear first upon the printing-paper, then those to the right in their order, and all in regular succession. As the greatest Variation that can be conveniently made in the sizes of the holes in the metal plates will not give sufficient variation to embrace every kind of printing process from the quickest to the slowest, I extend the time required for the characters at the left to appear by causing the light which is admitted through the perforations in the plate 9 to pass through a thickness of opal glass or translucent material instead of through plain or ground glass. I preferably let the light which falls on the characters at the right, or the first sixteen figures, to pass through plain or ground glass and that which falls upon the characters at the left, or the sixteen letters, to pass through opal glass.

If a test platinotype, carbon, or other similar print be first tested with the meter and the figure or letter which is just appearing when the test-print is properly exposed is ascertained, any number of succeeding correctlyexposed prints can be easily made, whatever be the actinic value of the light, by exposing the print and the actinometer at the same time and noting when the same test number or letter appears, and in the ease of a negative, if the figure or letter is marked upon it, correctly-exposed copies can be made from it at any time by noting the appearance of this figure or letter, as before explained. \Vhen the meter is opened, it will be found that the figures and letters printed upon the sensitive paper are graduated in density, each succeeding one being fainter and fainter until at length a certain number or letter becomes the last one readable. lVhen this let ter or number in its appearance corresponds with the time of the correct exposure of any print, it is called the test number or letter for all succeeding prints from the same negative and on the same paper. I may, however, as shown in Fig. 4:, dispense with the compound plate of plain or ground glass and opal glass (shown as placed between the perforated plate 9) and the sheet 17, of glass, carrying the figures, the space between the perforated plate and the glass being void and the proper distance between them being maintained either by packing of the requisite thickness or by a special configuration of the case or in any other suitable way. The scale of light, however, in this case would obviously be shorter than in the way before described.

My improvement is well adapted to accomplish the object for which it is intended, and,

Having fully described my invention, I claim as new and desire to secure by Letters Patent 1. In an actinometer,a metal plate provided with a plurality of openings of different sizes, a transparent plate provided with a plurality of designating numerals corresponding in number with the openings in said plate, and intervening plate of opal glass, and means for holding sensitized material adjacent to said transparent plate, substantially as and for the purpose described.

2. The herein-described actinometer, comprising a casing open at the bottom, a plate of opal glass mounted therein and covering said open bottom, a metal plate mounted thereon and provided with a plurality of openin gs of different sizes, said holes being arranged in two series, and the said perforations being the largest at the commencement of each series and gradually growing smaller to the end thereof, two plates of opal glass mounted on said metal plate and completely covering the same, each plate being adapted to cover one of said series of openings, and each being of a different degree of density, a transparent plate provided with suitable characters arranged in series which correspond in number and arrangement with the perforations in said metal plate, and a hinged cover provided with means for holding a sheet of sensitized material, substantially as and for the purpose described.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of the subscribing witnesses, this 19th day of January, 1897.

GEORGE FREDERICK IVYNNE. lVitnesses H. M. BROOKFIELD Din Ins,

T. E. BELLIs. 

